The London Underground is a beacon of clarity in visual communication. The tube map, using the supreme Gill Sans typeface beloved of regional British railways in the art deco years, is a masterpiece of design and possibly the easiest-to-comprehend legend for a major city’s underground system in the world.

It makes it easy to move around the capital as both a tourist and a newcomer. OK, so sometimes it’s faster to walk over ground after you’ve factored in the subterranean distances you might cover changing lines – especially to the Central Line which is not so much in the bowels of the city as the bottom of the toilet pan itself – but that doesn’t matter. You can plot your journey from A to B with ease.

Except when you get to B that is, and the voice on the speakers instructs you to change at the next stop for another line or ‘alight here’ for somewhere well known and adjacent.

Alight? What is that all about? Is something on fire at this stop? Why do we settle for a word so arcane that we might as well be dismounting from our trusty steed? What’s wrong with ‘exit here’ ‘or leave the train here’ for Madame Tussaud’s or some such place? I can’t think what percentage of tourists have ‘alight’ in the armoury of their second, third or fourth language, but it can’t be many. It creates confusion. I’m all for the Reithian principles of educating one’s audience by driving the language in 6th gear, but not when it comes to the binary process of ‘help me decide if I get off here or not’.

No, the audio dimension of the London Underground falls short of the visual aspect. B-minus, could do better.